Kinglets
are a small family of very small arboreal birds in the Northern
Hemisphere. It is now undisputed that these tiny sprites deserve family
status, as they are an ancient lineage, but their true place in the
avian tree of life is still uncertain. As a group they are rather easy
to recognize: very tiny, flitty, insect-gleaners of coniferous forests,
all having a colorful crown pattern. The common and widespread example
in North America is Ruby-crowned Kinglet (left and
below) which leaves its summer home in coniferous forests to spread
widely in all sorts of woodlands in the lowlands for winter. This is
the plainest of the kinglets since its ruby-red crown of the male is
almost always hidden (but look for it in the bathing sequence below).
However, when the crest is erected, it is striking and dramatic. The
first Ruby-crowned Kinglet that I ever saw — back on Christmas Day 1965
— had its crest up and was very agitated, full of "personality." It
made a big impression on me, then a 13-year-old kid.

This
male Ruby-crowned Kinglet (below) has found a small mud puddle in the
trail at Andrew Molera SP, California, suitable for bathing. Note the
very thin black legs (with yellow feet, in the perched shot above); the
slim bill: and the black bar on the secondaries below the lower white
wingbar (white tips to greater coverts).

All six kinglets are in the genus Regulus. The other North American species is Golden-crowned Kinglet,
a very hard bird to see well since it sticks to the tops of dense
conifers, but here's a shot of a migrant at Pt. Reyes, California
(left). Golden-crowned Kinglet has an extremely high-pitched call that,
once learned, allows one to document their presence much more often.
The male has lovely red stripe within the yellow crown stripe if you
can ever see one decently. Females, like this, have simply a yellow
crown stripe.

The Old World species are tiny with colorful head patterns, as illustrated by their English names: Goldcrest R. regulus (entire Palearctic), Common Firecrest R. ignicapillus (w. Palearctic), Madeira Firecrest R. madeirensis, and Flamecrest R. goodfellowi (endemic to Taiwan). [Orangecrest R. (r.) teneriffae (Canary Is., sometimes called Canary Island Kinglet), is sometimes split from Goldcrest.]

It
is sure fun to look at some of these photos, because in the field these
birds seem to be always moving and difficult to see well. In western
North America, particularly west of the Sierra Nevada and Cascades from
California north to British Columbia, there is a significant field
identification problem between Ruby-crowned Kinglet (a winter visitor
to the lowlands) and Hutton's Vireo Vireo huttoni (a resident
of oak and oak/pine woods). Even beginning birders should learn to
separate these two common but similar species. I have a
now-somewhat-dated page on the Identification of Hutton's Vireo v. Ruby-crowned Kinglet.

Martens
& Päckert (2006) explain that the very small size of these
passerines is adaptive, "allowing regulids to exploit a special
foraging niche on the thinnest of branches and in outermost canopies.
In the case of those species which specialize on conifers, small size
is particularly advantageous because it lets them manoeuvre in the
small species between needles, or even perch on the needles
themselves."

Kinglets
are traditionally treated as a subfamily of the Sylviidae (Old World
warblers; Voous 1977, Urban et al. 1997), which was even the tentative
plan for the Handbook of the Birds of the World project when
it began. Some authors placed it as part of a broader Muscicapidae
(Mayr & Amadon 1951, A.O.U. 1983) while Sibley & Monroe (1990)
noted that "molecular data support ranking this group as a family of
uncertain affinities (Sibley & Ahlquist 1990)" and placed them
between the Bulbuls and Old World warblers.

All of
that occurred before the dramatic changes wrought be more direct mtDNA
and (later) nuclear DNA evidence, which led to the "Break-up of the Old World Warblers"
in the early 21st century. We now know that they are an ancient lineage
— this was clear enough that by the time the applicable volume of the Handbook of the Birds of the World
was published (Martens & Päckert (2006), the editors had
changed their minds and elevated this small group to full Family
status. Where they should be placed in the grand scheme of things is,
however, still uncertain. They are apparently a very early offshoot in
the Muscicapoidea [e.g., Barker et al. (2004), Treplin et al. (2008)]
but whether they are closest to creepers or wrens or waxwings of
something else is still a mystery.

But let's not worry about that too much. Let's just marvel at another Graham Catley photo — a Common Firecrest giving us a great look at that fiery crown!